# std::chrono::weekday::operator++, std::chrono::weekday::operator--

From cppreference.com
< cpp‎ | chrono‎ | weekday

constexpr std::chrono::weekday& operator++() noexcept; | (1) | (since C++20)
constexpr std::chrono::weekday operator++( int ) noexcept; | (2) | (since C++20)
constexpr std::chrono::weekday& operator--() noexcept; | (3) | (since C++20)
constexpr std::chrono::weekday operator--( int ) noexcept; | (4) | (since C++20)

Adds or subtracts 1 from the weekday value, reducing the result modulo 7 to an integer in the range `[`​0​`,` 6`]`.

1,2) Performs *this += std::chrono::days{1};.
3,4) Performs *this -= std::chrono::days{1};.

### Parameters

(none)

### Return value

1,3) A reference to this `weekday` after modification.
2,4) A copy of the `weekday` made before modification.

### Notes

After a call to one of these functions, `ok()` is always true.

### Example

Run this code

    #include <cassert>
    #include <chrono>
    #include <iostream>

    int main()
    {
        std::cout << std::boolalpha;

        std::chrono::weekday wd{0}; // Sunday is 0 or 7

        --wd;
        std::cout << (wd == std::chrono::Saturday) << ' ';

        ++wd;
        std::cout << (wd == std::chrono::Sunday) << '\n';

        wd = std::chrono::weekday{13};
        assert(!wd.ok());
        wd++;
        assert(wd.ok());
    }

Output:

    true true

### See also

operator+=operator-= | adds or subtracts a number of days (public member function)
operator+operator- (C++20) | performs arithmetic on `weekday`s (function)

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